TY - JOUR
T1 - Fano-Kondo resonance versus Kondo plateau in an Aharonov-Bohm ring with an embedded quantum dot
AU - Eto, Mikio
AU - Sakano, Rui
N1 - Funding Information:
We appreciate fruitful discussions with Dr. Akira Oguri. This work was partially supported by JSPS KAKENHI Grants No. JP26220711 and No. JP15H05870 and JST-CREST Grant No. JPMJCR1876.
PY - 2020/12/1
Y1 - 2020/12/1
N2 - We theoretically examine the transport through an Aharonov-Bohm ring with an embedded quantum dot (QD), the so-called QD interferometer, to address two controversial issues regarding the shape of the Coulomb peaks and measurement of the transmission phase shift through a QD. We extend a previous model [B. R. Bulka and P. Stefański, Phys. Rev. Lett. 86, 5128 (2001)PRLTAO0031-900710.1103/PhysRevLett.86.5128; W. Hofstetter, J. König, and H. Schoeller, ibid. 87, 156803 (2001)PRLTAO0031-900710.1103/PhysRevLett.87.156803] to consider multiple conduction channels in two external leads, L and R. We introduce a parameter pα (|pα|≤1) to characterize a connection between the two arms of the ring through lead α (=L, R), which is the overlap integral between the conduction modes coupled to the two arms. First, we study the shape of a conductance peak as a function of energy level in the QD, in the absence of electron-electron interaction U. We show an asymmetric Fano resonance for |pL,R|=1 in the case of single conduction channel in the leads and an almost symmetric Breit-Wigner resonance for |pL,R|<0.5 in the case of multiple channels. Second, the Kondo effect is taken into account by the Bethe ansatz exact solution in the presence of U. We precisely evaluate the conductance at temperature T=0 and show a crossover from an asymmetric Fano-Kondo resonance to the Kondo plateau with changing pL,R. Our model is also applicable to the multiterminal geometry of the QD interferometer. We discuss the measurement of the transmission phase shift through the QD in a three-terminal geometry by a "double-slit experiment."We derive an analytical expression for the relation between the measured value and the intrinsic value of the phase shift.
AB - We theoretically examine the transport through an Aharonov-Bohm ring with an embedded quantum dot (QD), the so-called QD interferometer, to address two controversial issues regarding the shape of the Coulomb peaks and measurement of the transmission phase shift through a QD. We extend a previous model [B. R. Bulka and P. Stefański, Phys. Rev. Lett. 86, 5128 (2001)PRLTAO0031-900710.1103/PhysRevLett.86.5128; W. Hofstetter, J. König, and H. Schoeller, ibid. 87, 156803 (2001)PRLTAO0031-900710.1103/PhysRevLett.87.156803] to consider multiple conduction channels in two external leads, L and R. We introduce a parameter pα (|pα|≤1) to characterize a connection between the two arms of the ring through lead α (=L, R), which is the overlap integral between the conduction modes coupled to the two arms. First, we study the shape of a conductance peak as a function of energy level in the QD, in the absence of electron-electron interaction U. We show an asymmetric Fano resonance for |pL,R|=1 in the case of single conduction channel in the leads and an almost symmetric Breit-Wigner resonance for |pL,R|<0.5 in the case of multiple channels. Second, the Kondo effect is taken into account by the Bethe ansatz exact solution in the presence of U. We precisely evaluate the conductance at temperature T=0 and show a crossover from an asymmetric Fano-Kondo resonance to the Kondo plateau with changing pL,R. Our model is also applicable to the multiterminal geometry of the QD interferometer. We discuss the measurement of the transmission phase shift through the QD in a three-terminal geometry by a "double-slit experiment."We derive an analytical expression for the relation between the measured value and the intrinsic value of the phase shift.
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U2 - 10.1103/PhysRevB.102.245402
DO - 10.1103/PhysRevB.102.245402
M3 - Article
AN - SCOPUS:85097640195
VL - 102
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 2469-9950
IS - 24
M1 - 245402
ER -